"One would think that if the two got together then all the distribution would probably go to Australia for the combined company," Mr Beattie said.
"The book publishing industry in New Zealand is based on the North Shore of Auckland and these two are the two big players ... there's no question that if they merged the staff would be reduced - I'd say by at least a third."
He said authors and their agents would also be left with one less publisher to approach for publication and the possible merger could lessen competition.
It was unlikely to result in more expensive books for consumers, Mr Beattie said, but it could make life more difficult for writers negotiating book deals.
"It would have to reduce competition - they are two intensively competitive companies."
A Random House New Zealand spokeswoman declined to comment on the merger talks, while Penguin Books NZ provided only Pearson's statement.
Publishers Association of NZ president Kevin Chapman said it was too early to say what local effect the merger might have.
"All there is is a possible deal, and until the deal is firm and you know what the structures are you don't know what impact anything will have because there is so many ways to slice and dice these businesses," he said. "From the association's point of view we'll wait and see what happens."
Ian Whittaker, a London-based analyst at Liberum Capital, told the Bloomberg news agency a merger made strategic sense for Pearson.
The strength of a combined Random House and Penguin could give the firms more power against big buyers, such as online retail giant amazon.com, which had the ability to drive down prices, Mr Whittaker said.
"In an industry that is facing structural problems the easiest way to get profits are synergies and cost-cutting."
The big six
* Penguin Group
* Random House
* HarperCollins
* Georg von Holtzbrinck Publishing Group/Macmillan
* Hachette
* Simon & Schuster